It is pointless to schedule meetings where the agenda will get derailed in the first 5 minutes and a dozen engineers/managers will end up having bike shedding debates. And your engineers are correct that such discussions always turn into popularity contests and junior voices end up getting drowned out.

A better approach is to appoint a single tech lead, give them the freedom to make technical decisions, have them write a RFC/tech spec, and have others review the spec (by commenting on it and asking questions). Once there is consensus on the major items then development can proceed.